crypto: ahash - Use GFP_KERNEL in unaligned setkey
[linux-2.6.git] / crypto / ahash.c
1 /*
2  * Asynchronous Cryptographic Hash operations.
3  *
4  * This is the asynchronous version of hash.c with notification of
5  * completion via a callback.
6  *
7  * Copyright (c) 2008 Loc Ho <lho@amcc.com>
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License as published by the Free
11  * Software Foundation; either version 2 of the License, or (at your option)
12  * any later version.
13  *
14  */
15
16 #include <crypto/internal/hash.h>
17 #include <crypto/scatterwalk.h>
18 #include <linux/err.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/seq_file.h>
24
25 #include "internal.h"
26
27 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
28 {
29         return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
30                             halg);
31 }
32
33 static int hash_walk_next(struct crypto_hash_walk *walk)
34 {
35         unsigned int alignmask = walk->alignmask;
36         unsigned int offset = walk->offset;
37         unsigned int nbytes = min(walk->entrylen,
38                                   ((unsigned int)(PAGE_SIZE)) - offset);
39
40         walk->data = crypto_kmap(walk->pg, 0);
41         walk->data += offset;
42
43         if (offset & alignmask)
44                 nbytes = alignmask + 1 - (offset & alignmask);
45
46         walk->entrylen -= nbytes;
47         return nbytes;
48 }
49
50 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
51 {
52         struct scatterlist *sg;
53
54         sg = walk->sg;
55         walk->pg = sg_page(sg);
56         walk->offset = sg->offset;
57         walk->entrylen = sg->length;
58
59         if (walk->entrylen > walk->total)
60                 walk->entrylen = walk->total;
61         walk->total -= walk->entrylen;
62
63         return hash_walk_next(walk);
64 }
65
66 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
67 {
68         unsigned int alignmask = walk->alignmask;
69         unsigned int nbytes = walk->entrylen;
70
71         walk->data -= walk->offset;
72
73         if (nbytes && walk->offset & alignmask && !err) {
74                 walk->offset += alignmask - 1;
75                 walk->offset = ALIGN(walk->offset, alignmask + 1);
76                 walk->data += walk->offset;
77
78                 nbytes = min(nbytes,
79                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
80                 walk->entrylen -= nbytes;
81
82                 return nbytes;
83         }
84
85         crypto_kunmap(walk->data, 0);
86         crypto_yield(walk->flags);
87
88         if (err)
89                 return err;
90
91         if (nbytes) {
92                 walk->offset = 0;
93                 walk->pg++;
94                 return hash_walk_next(walk);
95         }
96
97         if (!walk->total)
98                 return 0;
99
100         walk->sg = scatterwalk_sg_next(walk->sg);
101
102         return hash_walk_new_entry(walk);
103 }
104 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
105
106 int crypto_hash_walk_first(struct ahash_request *req,
107                            struct crypto_hash_walk *walk)
108 {
109         walk->total = req->nbytes;
110
111         if (!walk->total)
112                 return 0;
113
114         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
115         walk->sg = req->src;
116         walk->flags = req->base.flags;
117
118         return hash_walk_new_entry(walk);
119 }
120 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
121
122 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
123                                   struct crypto_hash_walk *walk,
124                                   struct scatterlist *sg, unsigned int len)
125 {
126         walk->total = len;
127
128         if (!walk->total)
129                 return 0;
130
131         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
132         walk->sg = sg;
133         walk->flags = hdesc->flags;
134
135         return hash_walk_new_entry(walk);
136 }
137
138 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
139                                 unsigned int keylen)
140 {
141         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
142         unsigned long alignmask = crypto_ahash_alignmask(tfm);
143         int ret;
144         u8 *buffer, *alignbuffer;
145         unsigned long absize;
146
147         absize = keylen + alignmask;
148         buffer = kmalloc(absize, GFP_KERNEL);
149         if (!buffer)
150                 return -ENOMEM;
151
152         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
153         memcpy(alignbuffer, key, keylen);
154         ret = ahash->setkey(tfm, alignbuffer, keylen);
155         kzfree(buffer);
156         return ret;
157 }
158
159 static int ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
160                         unsigned int keylen)
161 {
162         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
163         unsigned long alignmask = crypto_ahash_alignmask(tfm);
164
165         if ((unsigned long)key & alignmask)
166                 return ahash_setkey_unaligned(tfm, key, keylen);
167
168         return ahash->setkey(tfm, key, keylen);
169 }
170
171 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
172                           unsigned int keylen)
173 {
174         return -ENOSYS;
175 }
176
177 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
178 {
179         struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
180         struct ahash_alg *alg = crypto_ahash_alg(hash);
181
182         if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
183                 return crypto_init_shash_ops_async(tfm);
184
185         hash->init = alg->init;
186         hash->update = alg->update;
187         hash->final  = alg->final;
188         hash->digest = alg->digest;
189         hash->setkey = alg->setkey ? ahash_setkey : ahash_nosetkey;
190
191         return 0;
192 }
193
194 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
195 {
196         if (alg->cra_type == &crypto_ahash_type)
197                 return alg->cra_ctxsize;
198
199         return sizeof(struct crypto_shash *);
200 }
201
202 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
203         __attribute__ ((unused));
204 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
205 {
206         seq_printf(m, "type         : ahash\n");
207         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
208                                              "yes" : "no");
209         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
210         seq_printf(m, "digestsize   : %u\n",
211                    __crypto_hash_alg_common(alg)->digestsize);
212 }
213
214 const struct crypto_type crypto_ahash_type = {
215         .extsize = crypto_ahash_extsize,
216         .init_tfm = crypto_ahash_init_tfm,
217 #ifdef CONFIG_PROC_FS
218         .show = crypto_ahash_show,
219 #endif
220         .maskclear = ~CRYPTO_ALG_TYPE_MASK,
221         .maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
222         .type = CRYPTO_ALG_TYPE_AHASH,
223         .tfmsize = offsetof(struct crypto_ahash, base),
224 };
225 EXPORT_SYMBOL_GPL(crypto_ahash_type);
226
227 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
228                                         u32 mask)
229 {
230         return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
231 }
232 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);
233
234 static int ahash_prepare_alg(struct ahash_alg *alg)
235 {
236         struct crypto_alg *base = &alg->halg.base;
237
238         if (alg->halg.digestsize > PAGE_SIZE / 8 ||
239             alg->halg.statesize > PAGE_SIZE / 8)
240                 return -EINVAL;
241
242         base->cra_type = &crypto_ahash_type;
243         base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
244         base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
245
246         return 0;
247 }
248
249 int crypto_register_ahash(struct ahash_alg *alg)
250 {
251         struct crypto_alg *base = &alg->halg.base;
252         int err;
253
254         err = ahash_prepare_alg(alg);
255         if (err)
256                 return err;
257
258         return crypto_register_alg(base);
259 }
260 EXPORT_SYMBOL_GPL(crypto_register_ahash);
261
262 int crypto_unregister_ahash(struct ahash_alg *alg)
263 {
264         return crypto_unregister_alg(&alg->halg.base);
265 }
266 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);
267
268 int ahash_register_instance(struct crypto_template *tmpl,
269                             struct ahash_instance *inst)
270 {
271         int err;
272
273         err = ahash_prepare_alg(&inst->alg);
274         if (err)
275                 return err;
276
277         return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
278 }
279 EXPORT_SYMBOL_GPL(ahash_register_instance);
280
281 void ahash_free_instance(struct crypto_instance *inst)
282 {
283         crypto_drop_spawn(crypto_instance_ctx(inst));
284         kfree(ahash_instance(inst));
285 }
286 EXPORT_SYMBOL_GPL(ahash_free_instance);
287
288 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
289                             struct hash_alg_common *alg,
290                             struct crypto_instance *inst)
291 {
292         return crypto_init_spawn2(&spawn->base, &alg->base, inst,
293                                   &crypto_ahash_type);
294 }
295 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);
296
297 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
298 {
299         struct crypto_alg *alg;
300
301         alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
302         return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
303 }
304 EXPORT_SYMBOL_GPL(ahash_attr_alg);
305
306 MODULE_LICENSE("GPL");
307 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");